Fuel cell devices convert chemical energy directly into electrical energy without combustion. The immediate benefit is much higher energy conversion efficiency and the drastic reduction of pollutants. Solid-oxide fuel cells (SOFC), in particular, are able to utilize existing widely used hydrocarbon fuel to simultaneously generate thermal and electrical power with combined heat and power (CHP) efficiency of over 80%. In comparison, internal-combustion engines (ICE) provide 25-30% efficiency with most of the energy loss in the form of exhaust heat and pollution. SOFC technology therefore can significantly reduce the fuel consumption as well as pollutant emission of vehicles, and without the need of exotic fuels.
A critical step in making these devices practical is developing electrode and electrolyte components with high efficiency and high resistance to aging and contamination. The electrochemical reactions occur in a narrow zone along the three-phase boundary (TPB), where the three reaction elements: cathode, solid electrolyte, and gas are in contact. Better electrochemical performances are expected for components with larger TPB length per unit area. Much of SOFC research and development efforts are therefore focused on producing nano-porous structures with maximum TPB length as well as optimizing operating conditions that lead to high performance and corrosion and contamination resistance, e.g. from sulfur.